Where did this come from? Can you send the link to the site? Sheila
_____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, February 26, 2007 8:18 AM To: [email protected] Subject: [Chihuahuas] A little bit about merle genetics There are better was to explaining this but here's a little information. There is no such thing as a sable merle gene or a red or blue merle gene. There is only a merle gene. Merle is an INCOMPLETE DOMINATE gene, which means this gene will show up in it's offspring. Merle is also a dilution gene, that is, it lightens whatever the coat color would otherwise have been. The lightening is not spread evenly over the coat, but leaves patches of undiluted color scattered over the dog's body. Also, the lightening seems to work primarily on the black pigment in the coat, so any tan on the face stays even. Note that "black" as used here includes the brown color. One dose of the merle gene on an otherwise black dog produces a blue merle - a more or less bluish gray dog dappled with black spots. Tan points - the tan spots over the eyes, on the sides of the muzzle, on the legs and under the tail of a tricolor dog - will still be there in the merled tricolor. If the tan spots would not be present in a black dog, tan will not be present in the merled black either, and the dog will blue merle and white without tan. One dose of the merle gene on an otherwise sable dog produces a sable merle. Sable merles are less predictable in color than blue merles, and may range anywhere from an apparent sable, often with a pinkish or orange cast to its coat, to something that looks like a very rusty blue merle. White markings remain on the merled dog, and may even be slightly more prominant. Merle acts on the dark pigment in the iris of the eye just as it does on the coat, so merle dogs often have part or all of the eye blue. (This does not affect their vision, though since it happens to some extent in the retina as well it may make it harder to diagnose certain eye problems.) Notice what was said was a single dose of the merle gene. There are always two copies of a gene, alike or different, in any dog. If we call the merle gene M and the non-merle gene m, any given dog can be mm, Mm or MM. The mm dog is the normal, full-colored tri, bi-color, or sable, or liver (red) in Australian Shepherds. The Mm Cocker is a blue merle, or brown merle, etc,depending on what color it would have been without the merling gene. An MM dog, often called a double merle or a homozygous merle, will be mostly white and sometimes deaf or blind and often with other physical problems. Some MM puppies are born completely without eyes. On average over a large number of litters, breeding merle to merle will produce one fourth full colored dogs, one half merles and one fourth defective whites. Breeding merle to full color will produce one half full color and one half merles, but no defective whites. The merle to full color breeding, then, produces just as many merles as does the merle to merle breeding, and without the danger of defective puppies. The safe breeding for a merle, then, is to a non-merle mate. This breeding should produce all healthy puppies, and about half will be merles. To breed in this way, it is important to know which dogs are merles. This is one of the reasons experienced breeders rarely breed blue merles to sables, or roans as this mating may produce sable merles or merles to the inexperienced breeder to appear incorrectly as roans.. Sable merles are no more likely to have health problems than any other color. Sometimes you cannot tell a sable is a merle unless you see it on the tips of it's ears or the eye or eyes are blue or blue flecked.,. The real arguement against sable merles is that they may be mistaken for normal sables. If two such sable merles were mated together, the resulting litter could contain defective whites. The sable gene can also mask the merle, and as the dog ages it may be next to impossible to tell by looking that this IS a merle dog. _____ AOL now offers free email to everyone. Find out more about what's free from AOL at <http://pr.atwola.com/promoclk/1615326657x4311227241x4298082137/aol?redir=ht tp%3A%2F%2Fwww%2Eaol%2Ecom> AOL.com.
